1. Field of the Invention
The present invention relates generally to microlenses and microlens arrays and methods of forming microlenses aid microlens arrays.
2. Description of the Prior Art
Microlenses have been fabricated using a number of different methods in the past including planar ion-exchange, photoresist and plastic flow, microjet printing, reactive ion etching and laser ablation. However, while many of these techniques may produce acceptable microlenses, these prior methods frequently use non-standard processes and are not easily integrated into the manufacturing of optoelectronic devices.
It is therefore an object of the invention to provide a method for producing microlenses that can be directly integrated into the fabrication process of microoptical systems.
It is another object of the present invention to provide an epitaxial growth method that is capable of producing highly nonplanar features that are free from macroscopic facetting.
According to one aspect of the present invention, there is provided a microlens having a focal length of 50 xcexcm or less.
According to a second aspect of the present invention, there is provided an array of microlenses mounted on a substrate, each of the microlenses having a focal length of 50 xcexcm or less.
According to a third aspect of the present invention, there is provided a non-planar of microstructure comprising a first layer comprising at least one first CVD material selected from the group consisting of a rapidly oxidizing CVD material and an oxygen-containing CVD material; and a covering layer comprising at least one second CVD material selected from the group consisting of a slowly oxidizing CVD material and a substantially oxygen free CVD material, the covering layer substantially covering a top surface of the first layer.
According to a fourth aspect of the present invention, there is provided a method for making at least one non-planar microstructure comprising the steps of depositing at least one CVD material through at least one window of a mask layer and an opening in a spacer layer beneath the mask layer to form a non-planar microstructure on a substrate, the mask layer being separated from the substrate by the spacer layer and overhanging the spacer layer; and removing the mask layer and the spacer layer by applying a removal solution to the mask layer and the spacer layer which does not react with the non-planar microstructure.
According to a fifth aspect of the present invention, there is provided a vertical cavity surface emitting laser structure comprising: a vertical cavity surface emitting laser, and at least one non-planar microstructure at one end of the vertical cavity surface emitting laser.
According to a sixth aspect of the present invention, there is provided a method for making at least one non-planar microstructure comprising the steps of: depositing at least one CVD material through at least one window of a shadow mask to form a non-planar microstructure on a substrate, the shadow mask including an overhanging region which overhangs a spacer region which is directly bonded to said substrate.
Other objects and features of the present invention will be apparent from the following detailed description of the preferred embodiments.